Tour a Prewar Penthouse That’s Built Around a Rooftop Water Tower

There’s no more familiar symbol of New York grit than the exposed rooftop water tank. In the chic stretches of the Upper East Side, though, the utilitarian tends to get dressed up, and prewar buildings typically have their tanks elegantly encased in towers that match the architecture below. Lili and Lee Siegelson’s penthouse not only lies on the floor directly below one of those towers; like no other apartment you’ve seen, it also reaches up into the water tower’s brick shell, with a few thousand gallons stored directly overhead.

When Olson Kundig Architects began an overhaul of the apartment five years ago, Lee had been living there for a half-decade, having purchased the eccentric tower space — effectively the building’s 18th floor, and tall enough to have its own small mezzanine — as a bachelor in 2004. After he married Lili and they had two kids, the couple added the (much more conventional) 17th floor, and now they had to figure out how to put it all together. “At some point,” says Tom Kundig, principal of Olson Kundig, “you just go, ‘At what point are we grown up? When do we start to make a true home?’ They might not agree with that,” he adds, starting to laugh, “but I see it all the time.”

Making a true home entailed completely gutting the 18th floor and cutting a stairwell through from below. The architects custom-designed many of the interior fittings, including a banquette-bench-table dining nook in the corner of the living room. Their polished refinements of utilitarian materials can be seen in details like the exposed-pulley handle that opens the upper windows. The Siegelsons “came to us because of our industrial sensibility,” Kundig says. “What I think of as industrial is authentic; it embraces the function of the place, the materials, and it’s an expression of how it all works together, and that is what they really liked.” To that end, they left the exposed brick walls alone and used steel-chain mesh to cover the huge arched windows in the living room, which extend nearly to the 19-foot ceiling. “It’s really tough and filters the light, and it’s never going to deteriorate in the sun.” They also added a fireplace and chimney — which, if you think about it, is a little funny with all that water overhead. “Thousands of gallons, just right up there above the apartment!” says one of Kundig’s colleagues when I mention it. No wonder the surrounding rooftop garden is so green.

A water tank feeding the whole building occupies the very top of the tower. The lower section of the tower has 19-foot ceilings and contains the kitchen and living room plus a small office mezzanine. A rooftop garden designed by David Kelly at Rees Roberts + Partners surrounds the windows like a lush green cushion. The rest of the apartment lies below, on the building’s highest full floor.

Photo: Jason Schmidt

The architects had to compromise on the staircase between the main level and the tower: They’d designed it as a single welded unit, but it wasn’t finished on the day a crane was available to hoist it up. Instead, it was made in sections and brought in via the freight elevator later on.

Photo: Jason Schmidt

The fireplace and chimney are newly added, with a fire screen echoing the original grillwork in the tower’s vent windows high above. The sheer curtains are metal mesh, akin to chain mail. Olson Kundig also replaced the aluminum windows with blackened steel, a better match with the rest of the building. The built-in furniture is all by Olson Kundig; the sectional sofa, fabricated by Walter P. Sauer in Brooklyn, is upholstered in Loro Piana cashmere.

Photo: Jason Schmidt

The steel bookshelves are integral with, and help support, the stairs.

Photo: Jason Schmidt

The handrail is a steel rod with a leather wrap (to match the covering on the treads).

Photo: Jason Schmidt

The glass-and-steel desk on the mezzanine was built by Jim Zivic. Its lucky user has unlimited views and light.

Photo: Jason Schmidt

The master bedroom, on the lower level, opens onto its own small garden terrace. The bed was custom-designed for the room by Olson Kundig.